KaolinMaze in Clay-Deposits of North-West India

Kaolin clays are used as a precursor and raw-material in manufacturing industry. They are abundant in mines spread across the country. They consist of kaolinite and its polymorphs, and halloysite, each species having its characteristics crystallite and charge properties, and surface morphology, and thereby each one of them performs unique tasks. They are inrerum-natura of novel nanofabrication technology. For example, halloysite might be a substitute of carbon nanotube, especially for farming applications. Similarly, nano-kaolinite and its polymorphs might be useful receptacles for holding anionic plant nutrients. Despite numerous attempts, their precise identification remains inconclusive. We, therefore, attempted to characterize kaolin clays in some of the Indian deposits. Theywere sampled from five mines of northwest India, and characterized byX-ray diffraction, Fourier Transform Infrared Spectroscopy, and thermal analysis. The simultaneous occurrence of first order X-ray diffraction peaks at 1.01 and 0.93 nm, and absence of 0.7 nm peaks in S1 (Jodhpur), S2 (Delhi), S3 (Udaipur), and S5 (Ahmedabad) samples indicated presence of halloysite. Samples S1 and S2 followed by S4 (Varoda) and S5 showed substantial loss of weight, which could be attributed to the loss of water from their hydration state. Infra-red absorption frequency at 3695, 3676, 3647 and 3620 cm⁻¹in all samples confirmed hydroxyl stretching, but appearance of characteristics bands at 1629 and 1648 cm⁻¹ that represent water bending arising from structural and coordinated water in halloysitewere observed only in sample S1. Our data confirmed fully hydrated halloysite in sample S1, and partiallyhydrated halloysite in samples S3 and S4, and samples S2and S5 contain kaolinite or, its polymorphs.